Περίληψη:
In extending volcanic arcs such as the Aegean, tectonic processes exert
a significant control on magmatism. Spanning scales from 1 to 10s of km,
volcanic vents, edifices, and eruptive centers follow the orientation
of, and are located near, fault zones. Whether this tectonic control on
magmatism results from individual faults/fractures weakening the crust
or because regional stresses control magma input into the crust is
debated. Here we investigate the scales of tectonic and magmatic
interactions, specifically focusing on the role of local-scale (<10 km)
faults/fractures in controlling magmatism. We infer local-scale
fault/fracture orientations from anisotropic active-source P-wave
travel-time tomography to investigate tectonic and magmatic interactions
in the upper crust of Santorini Volcano, Greece, and the actively
deforming region to the east. We use the anisotropy magnitude and
seismic velocity reduction to model the relative distribution of both
consistently oriented and randomly oriented faults/fractures. Our
results show that oriented faulting/fracturing resulting from
regional-scale (>10 km) tectonic stresses is distributed broadly across
the region at 2-3 km depth, approximately paralleling volcanic/magmatic
features. On a local-scale, magmatism is neither localized in areas of
higher oriented fault/fracture density, nor is it accommodating enough
extensional strain to inhibit oriented faulting/fracturing of host rock.
The alignment of magmatic features shows strong tectonic control despite
the lack of correlation with local oriented fault/fracture density.
These results suggest that magmatic processes are strongly influenced by
regional-scale, not local-scale, tectonic processes. We infer regional
processes have a greater impact on magmatism than local features due to
their greater effect at depth.
Συγγραφείς:
Heath, B. A.
Hooft, E. E. E.
Toomey, D. R.
Paulatto, M. and
Papazachos, C. B.
Nomikou, P.
Morgan, V, J.
